Automatic feed mechanism for sewing machines



R. KOSROW 37,363,594

AUTOMATIC FEED MECHANIS M FOR SEWING MACHINES Jan. 16, 1968 Filed May12, 1965 6 Sheets-Sheet l Jan. 16, 1968 R. L. KOSROW 3,363,594

AUTOMATIC FEED MECHANISM FOR SEWING MACHINES Filed May 12, 1965 6Sheets-Sheet 2 R. L. KOSROW 3,363,594

AUTOMATIC FEED MECHANISM FOR SEWING MACHINES Jan. 16, 1968 6Sheets-Sheet 5 Filed May 12, 1965 wwwx Jan. 16, 1968 R. L. KOSROW3,363,594

AUTOMATIC FEED MECHANISM FOR SEWING MACHINES Filed May 12, 1965 6Sheets-Sheet 4.

l v I23 30 R. L. KOSROW 3,363,594

AUTOMATIC FEED MECHANISM FOR SEWING MACHINES Jan. 16, 1968 6Sheets-Sheet 5 Filed May 12; 1965 FIG. 9

Jan. 16, 1968 R. KOSROW 3,36 ,594

AUTOMATIC FEED MECHANISM FOR SEWING MACHINES Filed May 12, 1965 6Sheets-Sheet 6 United States Patent 3,363,594 AUTOMATIC FEED MECHANISMFOR SEWING MACHINES Robert L. Kosrow, Elk Grove Village, IlL, assignorto Union Special Machine Company, Chicago, 11]., a corporation ofIllinois Filed May 12, 1965, Ser. No. 455,151 18 Claims. (Cl. 112-210)ABSTRACT OF THE DISCLOSURE A back tacking mechanism for a sewing machinein which first sensing means including a first photoelectric cell iseffective to automatically feed the material being sewn in a forwarddirection, and second sensing means including a second photoelectriccell reverses the direction of feed for a period of time which isdependent upon the rate of discharge of a capacitor. The first sensingmeans then continues the advance of the material in the forwarddirection and is effective to automatically shut off the stitchingmechanism of the machine when the trailing edge of the material passestherebeneath.

This invention relates to a sewing machine and more particularly to anautomatically controlled feeding mechanism for changing the direction offeed of the material being sewn.

There has been developed an adjustable drive for the feeding mechanismof a sewing machine which is positive in action and highly efiicient.One such drive is disclosed, for example, in Daniel Patent No.3,033,141, granted May 8, 1962. In drives of this type, the direction offeed of the material being advanced through the machine may be readilyreversed, to perform back tacking or other stitching operations, inresponse to the actuation of a reversing lever by the machine operator.The machine also includes an additional manual control, customarily inthe form of a foot treadle, for starting and stopping the feedingmechanism.

In order to prevent the possibility of the stitching be comingunravelled, the seam being sewn frequently is locked in place at theleading and trailing edges of the material through the use of locking orback tacking stitches. To perform a back tacking operation on machinesof the foregoing type, it heretofore was necessary for the operator toslow down the machine sufficiently to be able to count the desirednumber of forward locking stitches, to then operate the reversing leverand count the number of reverse locking stitches, and to thereafterreturn to forward stitching for the sewing and completion of the seam.The operation required the use of both hands of the operator and wasparticularly disadvantageous in the formation of a back tack at thetrailing edge of the material because of the desirability that theoperator have his hands free to prepare succeeding pieces of materialfor seaming. The frequent actuation of the foot treadle and reversinglever in such prior machines has consumed an excessive amount of timeand has otherwise proved deficient in several respects.

One general object of this invention, therefore, is to provide a new andimproved feeding mechanism for sewing machines which enables theautomatic control of the direction of feed.

More specifically, it is an object of the invention to provide suchfeeding mechanism which is effective to automatically reverse thedirection of feed for a predetermined period of time.

Another object of the invention is to provide a feeding mechanism of thecharacter indicated for automatically Patented Jan. 16, 1968 performinga back tacking operation at the trailing edge of the material beingsewn.

A further object of the invention is to provide a novel feedingmechanism for sewing machines which is economical to manufacture andthoroughly reliable in operation.

In one illstrative embodiment of the invention, there is provided asewing machine having a reversible feeding mechanism and a stitchingmechanism which are connected through a drive clutch to a suitablesource of power. The drive clutch is controlled by a foot treadle forinitiating operation of the machine. To perform a back tacking or otherreversing operation, the machine includes an automatic control systemwhich is effective to actuate the feeding mechanism in both the forwardand the reverse direction in accordance with a predetermined sequencewithout the intervention of the operator of the machine.

In accordance with one feature of the invention, the automatic controlsystem comprises unique sensing means, such as a photoelectric cell andcooperating light source, for example, which is responsive to apreselected portion of the material being advanced through the stitchingmechanism to change the direction of feed for a predetermined period oftime. Thereafter, the operation of the feeding mechanism isautomatically continued in the initial direction to complete the seam.

In accordance with another feature of the invention, in severaladvantageous embodiments, there is provided additional photoelectricmeans for conditioning the 111achine for automatic operation and forbringing the machine to a stop upon the completion of the seam. Thearrangement is such that the machine automatically forms a back tackalong the trailing edge of the material and then shuts itself offwithout the intervention of the operator. With this arrangement, theoperator is free to arrange successive pieces of material for stitchingor to perform other ancillary operations during the formation of theseam.

In accordance with the further feature of certain goo-d embodiments ofthe invention, automatic operation of the machine is initiated by amanually controlled switch which may be actuated at substantially anypoint during the formation of the seam. The machine thereafterautomatically completes the seam, irrespective of its length, and formsa back tack of preselected length at the trailing edge of the material.

In accordance with a still further feature of the invention, in someembodiments, the actuation of the control switch to initiate automaticoperation also is effective to disengage the foot treadle of the machineuntil the ma- 1 chine has been brought to a stop following thecompletion of the seam.

The present invention, as well as further objects and features thereof,will be understood more clearly and fully from the following descriptionof certain preferred embodiments, when read with reference to theaccompanying drawings, in which:

FIGURE 1 is a front elevational view of a sewing machine in accordancewith one illustrative embodiment of the invention, with certain partsshown broken away;

FIGURE 2 is a side elevational view of the machine as seen from the leftof FIGURE 1, with portions of the supporting structure omitted forpurposes of clarity;

FIGURE 3 is a bottom view of a portion of the machine with the coverplate removed;

FIGURE 4 is a transverse vertical sectional View taken along the line4-4 in FIGURE 3;

FIGURE 5 is a horizontal sectional view taken generally along the line5-5 in FIGURE 1;

FIGURE 6 is a horizontal sectional view taken along the line 6-6 inFIGURE 1;

FIGURE 7 is an enlarged front elevational view of the portion of themachine shown in FIGURE 6;

FIGURE 8 is a schematic wiring diagram of a portion of the automaticcontrol circuit for the machine;

FIGURE 9 is a schematic wiring diagram of another portion of theautomatic control circuit;

FIGURE 10 is a side elevational view similar to a portion of FIGURE 2but illustrating a sewing machine in accordance with anotherillustrative embodiment of the invention; and

FIGURE 11 is a front elevational view of a portion of the machine shownin FIGURE 10.

Referring to the drawings, there is shown a lock-stitch sewing machineof the general type disclosed in somewhat greater detail in CovertPatent 2,977,910, granted Apr. 4, 1961. The machine includes a framestructure indicated generally at 15 which supports a sewing table 16. Avertical standard 17 extends upwardly from the table 15 and is providedwith an overhanging arm 18 which terminates in a needle head 19. Thehead 19 includes a vertically reciprocable stitching mechanism 20 ofconventional construction which is controlled by a drive shaft (notvisible in the drawings) longitudinally disposed within the arm 18. Theend of this shaft opposite that adjacent the head 19 is affixed to acombined handwheel and pulley 22.

The pulley 22 is driven through a V-belt 25 by a drive pulley 26. Thislatter pulley is mounted beneath the sewing table 16 and is connected toone side of a combined clutch-brake mechanism 28, the other side ofwhich is operated by an A.C. motor or other suitable source of drivingpower. The clutch-brake mechanism 28 iilustratively may be of the typedisclosed in Ingalls Patent 2,739,251, granted Mar. 20, 1956. Themechanism 28 includes an actuating pin 34 which is movable to the leftfrom the position shown in FIGURE 1 to engage the clutch portion of themechanism and transfer driving power from the motor 30 to the pulley 26,thereby operating the stitching mechanism 20 through the belt 25, thepulley 22 and the drive shaft within the overhanging arm 18. Uponmovement of the pin 34 to the right, the clutch is disengaged, andpositive braking action is applied to the pulley 26 to rapidly arrestthe stitching mechanism. Power is supplied to the motor 30 through acable 36, a main on-oif switch 37 and a plug 38.

The movements of the actuating pin 34 are controlled by an L-shapedlever 39 which is pivotally supported adjacent one end thereof by a pin40. The opposite end of the lever 39 is fixedly but adjustably securedto a substantially flat plate 41. Pivotally supported by the plate 41 isan upstanding lever 42 which is offset adjacent its upper end and isconnected to the plunger 43 of an automatic take-over solenoid 44. Thissolenoid is carried by a plate 45 which is mounted on the housing forthe motor 30 at the end thereof opposite that adjacent the clutchbrakemechanism 28. The plate 45 additionally supports a braking solenoid 46having a plunger 47 which is coaxially aligned with the plunger 43. Thesolenoid 46 is adjustably held in place on the plate 45 by screws 48 andis positioned such that the plunger 47 bottoms within the solenoid whenit is in its energized condition. The plunger 43 of the solenoid 44 issimilarly positioned by adjusting the angular relationship between thelever 39 and the plate 41 through the use of screws 49.

The facing ends of the plungers 43 and 47 are fixedly interconnectedsuch that the plungers move in unison. Upon energization of thetake-over solenoid 44, the plungers 43 and 47, together with the offsetlever 42, are carried in a downward direction to pivot the lever 38counterclockwise about the pin and thereby move the actuating pin 34 ina direction to engage the clutch portion of the clutch-brake mechanism28. Energization of the braking solenoid 46 urges the lever 42 upwardlyand pivots the lever 39 clockwise to move the pin 34 in a direction toprovide positive braking action, for purposes that will become morefully apparent hereinafter.

A pitman assembly 59 is connected between the flat plate 41 and a foottreadle 51. The assembly 50 comprises two elongated rods 52 and 53 whichextend downwardly from the plate 41 in spaced-apart parallelrelationship with each other. The upper end of the rod 52 is secured tothe plate 41 by a ball connection 54, and a clamp 55 is fastenedadjacent the lower end of the rod. The rod 53 is connected by a ballconnection 56 to the foot treadle 51, and this latter rod extendsupwardly from the foot treadle and is slidably disposed in a suitableaperture in the clamp 55.

Positioned around the rods 52 and 53 between the plate 41 and the clamp55 is a release clamp 58. As best shown in FIGURES 6 and 7, the clamp 53is maintained in rigid relationship with the rod 52 by set screws 5Q. Alever 60 is pivotally supported by the clamp 58 for movement about avertical axis. In the illustrated position, this lever is resilientlyheld against a locking portion 62 of the rod 53 by a coil spring 64. Theportion 62 is of reduced diameter such that the lever 66 normallyprevents vertical movement of the rod 53 with respect to the rod 52. Thelever 66 is connected by a horizontally extending link 65 to a treadlerelease solenoid 66 (FIG- URE 1). Upon energization of the solenoid 66,the lever 60 is pivoted in a counterclockwise direction from theposition shown in FIGURE 6 to permit free sliding movement between therods 52 and 53.

The material feeding mechanism of the machine is best shown in FIGURES35. This mechanism includes a horizontally extending drive shaft 70which is journalled beneath the table 16 and is suitably connected tothe drive shaft within the overhanging arm 18 by approprb ate gearing(not visible in the drawings) in the vertical standard 17. The driveshaft 70 is effective to produce a four-motion feeding movement of afeed bar 71 and an attached feed dog 72 (FIGURE 4). Thus, as more fullydescribed in the Daniel patent referred to above, the shaft 70 includesan eccentric 74 which is connected through a link 75 to a depending arm76 afiixed to the feed bar 71. As the shaft 70 rotates, the forward endof the bar 71 (the right end, as viewed in FIGURE 4) moves upwardly anddownwardly to produce corresponding movements of the feed dog 72. Asecond eccentric 78 on the shaft '76 is connected through a link 79 to afeed rocker 80 which is pivotally supported on a horizontally extendingstationary shaft 81. The rocker 8% is provided with an arcuate slot 82which extends substantially equal distances above and below the axis ofthe shaft 81. This slot carries a slide element 83 which is connectedthrough a link 84 to the depending arm 76. As the drive shaft 70rotates, the rocking movement of the rocker 8 0 acts on the element 83,the link 84 and the arm 76 to produce longitudinal reciprocating motionof the feed bar '71 and the feed dog 72. This movement, when coupledwith the movement of the feed dog in response to the eccentric 74,causes the feed dog to describe a generally elliptical path, as shownschematically at 85 in FIGURE 4.

The direction and extent of movement of the feed dog 72 along itselliptical path is determined by the position of the slide element 83within the arcuate slot 82. In cases in which the element 83 is disposedwithin the slot 82 above the axis of the stationary shaft 81, the feeddog 72 moves along its path in a direction to advance the material beingsewn forwardly through the stitching mechanism 20 (FIGURE 1). With theelement 83 below the axis of the shaft 31, the feed dog moves in theopposite or reverse direction. The greater the upward or downwardmovement of the element 83 from its dead center position, the greaterwill be the longitudinal movement of the feed dog, thereby providing acontrol over the length of the stitches.

As best shown in FIGURES 3 and 5 a bent lever 85 interconnects the slideelement 83 and one end of a rock shaft 87. The shaft 87 is supportedbeneath the table 16 in spaced parallel relationship with the driveshaft 70, and its opposite end is connected through arms 88 and 89 to aforwardly extending shaft 90. This latter shaft is provided with areversing lever 92 (FIGURE 1) which may be controlled either manually bythe operator of the machine or automatically by a reversing solenoid 94.The solenoid 94 is mounted on the vertical standard 17 and is adjustablyheld in place by screws 95. Upon movement of the lever 92 in acounterclockwise direction, as viewed in FIGURE 1, the slide element 83(FIGURE 4) is urged progressively above the level of the stationaryshaft 81 to operate the feeding mechanism in the forward direction.Conversely, clockwise movement of the lever 92 carries the element 83progressively below the level of the shaft 81 to reverse the directionof feed.

The reversing solenoid 94, together with the takeover solenoid 44, thebraking solenoid 46 and the threadle release solenoid 66, are operatedunder the control of a lever 97 and two photoelectric cells 98 and 99and cooperating light sources 100 and 181. The lever 97 is supported onthe upper surface of the table 16 and includes two sets of normally openswitch contacts 103 and 104, only the contacts 103 being visible inFIGURE 1. Upon movement of the lever 97 to the right from the positionshown in this figure, the contacts 103 and 104 close momentarily toinitiate the automatic operation of the sewing machine in a manner to bemore fully described hereinafter.

The light source 1110 for the photoelectric cell 98 is clamped to theneedle head 19 immediately above the stitching mechanism 20. The source109 directs a beam of light in a downward direction through atransparent plate (not visible in the drawings) in the table 16 to aprism 105 mounted therebeneath. The prism 195 bends the light beam atright angles and directs it toward the photocell 98 which is suitablyaffixed to the lower surface of the table. The light source 101 and thephotoelectric cell 99 are clamped to the needle head 19 adjacent theoutfeed side of the stitching mechanism 20, that is, to the right of themechanism as viewed in FIG- URE 2. The beam of light from this lattersource is reflected by the needle plate of the machine toward thephotocell 99.

The switch contacts 103 and 104, the photoelectric cells 98 and 99, andthe light sources 188 and 101 are electrically connected in a controlcircuit which is effective to actuate the take-over solenoid 44, thebraking solenoid 46, the treadle release solenoid 66 and the reversingsolenoid 94 in predetermined relationship with each other. Several ofthe individual components of the control circuit are mounted on a panel108 which is disposed above the table 16 and is supported by anupstanding rod 189. These components include five twoposition switches110114 and a pilot light 115 for lIlClleating the condition of thecircuit. Also mounted on the panel 108 is a variable resistor 117 whichcontrols the duration of application of positive braking action to themachine and a variable resistor 118 for controlling the duration ofreverse operation.

The control circuit is shown schematically in FIG- URES 8 and 9. Theportion of the circuit illustrated in FIGURE 8 includes the photocell 98and its light source 100 and is effective to condition the machine forautomatic operation and to bring it to a stop upon the completion of aseam. The circuit portion shown .in FIGURE 9 includes the photocell 99and the light source 101 and provides control over the formation of aback tack through energization of the reversing solenoid 94. Thedeenergized positions of the various relay contacts in the controlcircuit are shown by full lines in these 6 figures, while the energizedpositions of the contacts are shown by dotted lines.

Referring to FIGURE 8, the circuit includes supply lines 120 and 121which lead to opposite sides of an AC. power source 122 through thetwo-position switch 110. The pilot light is connected across the linesand 121 and is energized upon the closing of the switch 110 to providean indication that the circuit is in an active condition. The source 122also is connected to the motor 30 by conductors 119 and 123 and theonoff switch 37.

The lines 120 and 121 supply power to a photocell circuit shownschematically at 124. The circuit 124 is of conventional constructionand is effective to produce an output signal in response to theinterruption of the light beam from the light source 100 to thephotocell 98. This output signal appears in the winding of a relay 125having normally open contacts 126. One of the contacts 126 is connnectedthrough the two-position switch 111 to the line 120, while the othercontact leads through the winding 128a of a multicontact relay 128, aconductor 129, the manually controlled switch 103 and conductors 130 and131 to the line 121.

The relay 128 is provided with normally open contacts 132 and 133 andtransfer contacts 138, 139 and 140. The contacts 132 are interposedbetween the conductor 129 and the common terminal of the conductors 131iand 131. Upon energization of the relay 128, the contacts 132 are movedto their closed (dotted-line) position to complete a holding circuit forthe winding 128a. One of the contacts 133 is connected to a conductor135 leading to the supply line 120, while the other contact leads to aparallel circuit comprising the take-over solenoid 44 and the treadlerelease solenoid 66. The circuit is completed through the two-positionswitch 112 and a conductor 136 to the line 121.

The transfer contacts of the relay 128 comprise a movable contact 138and two stationary contacts 139 and 140. The movable contact 138 isconnected to the negative side of a condenser 142, the positive side ofwhich leads through a conductor 143 to one terminal of the winding of arelay 145. The opposite terminal of this winding is connected to thestationary contact 139 by a conductor 146. Connected in parallel acrossthe relay winding is a series circuit including a resistor 147 and thevariable resistor 117. In addition, the anode of a diode rectifier 148is connected to the conductor 143, while the cathode of the rectifierleads through a resistor 149 to the supply line 121. In the deenergizedcondition of the relay 128, the movable contact 138 is maintamed inengagement with the contact 139. Upon energization of the relay, thecontact 138 transfers from the contact 139 to the contact 14%), therebycompleting a circuit from the condenser 142, the contacts 138 and and aconductor 150 to the supply line 129.

The relay 145 includes normally open contacts 152 which are interposedbetween the supply line 128 and one terminal of the braking solenoid 46.The opposite terminal of the solenoid 46 is connected through thetwo-position switch 113 to the supply line 121.

In the portion of the control circuit shown in FIG- URE 9, the supplylines 120 and 121 are connected from the AC. source 122 to aphotoelectric circuit 155. The circuit 155 is generally similar to thecircuit 124 of FIG- URE 8 and is effective to produce an output signalin the Winding of a relay 156 upon the interruption of the light beamfrom the light source 191 to the photocell 99. The relay 156 includesnormally open contacts 157. One of the contacts 157 is connected by aconductor 158 to the line 120, while the other contact leads to oneterminal of the winding 169a of a multicontact transfer relay Themulticontact relay 161) includes a first set of transfer contacts whichcomprise a movable contact 162 and two stationary contacts 163 and 164.The movable contact 162 is connected to the terminal of the winding 160aopposite that leading to the supply line 120. The stationary contact 163is connected to the supply line 121 along a path which extends throughthe manually operable switch contacts 1114 and conductors 165 and 166,while the stationary contact 164 leads to the common terminal of theseconductors. Upon energization of the relay 160, the contact 162transfers from the contact 163 to the contact 164 to complete a holdingcircuit for the relay.

The relay 160 also includes a movable contact 167 and two stationarycontacts 168 and 16'9. The contact 167 is connected to the negativeterminal of a condenser 1719, the positive terminal of which leadsthrough a conductor 171, the winding of a relay 172 and a conductor 173to the stationary contact 168. A resistor 175 and the variable resistor118 are arranged in series between the conductors 171 and 173. The anodeof a diode rectifier 178 is connected to the conductor 171, while thecathode of the rectifier leads through a resistor 179 to the supply line121. The supply line 120 is connected to the contact 169 by a conductor180. The relay 172 is provided with normally open contacts 182 which areinterposed between the supply line 120 and one terminal of the reversingsolenoid 94. The opposite terminal of the solenoid 94 leads through theon-off switch 114 to the supply line 121.

At the start of a particular sewing operation, the operator of themachine moves the two-position switches 110-114 on the control panel 108(FIGURE 1) to their closed positions. In addition, the on-off switch 37is moved to its on position to energize the drive motor 30. The piecesof material to be sewn together are then placed on the table 16 and areadvanced through the stitching mechanism 20 by the feed dog 72 (FIGURE4). The operation of the mechanism 26 and the feed dog 72 is initiatedby depressing the foot treadle 51 to move the pitrnan assembly 50 in agenerally downward direction, as viewed in FIGURE 1, thereby pivotingthe L-shaped lever 39 counterclockwise about the pin 40 to carry theactuating pin 34 to the left and thus engage the clutch portion of theclutch-brake mechanism 28. During the time the machine is under manualcontrol, the stitching and feeding mechanisms may be arrested by movingthe treadle 51 in the opposite direction to carry the pin 34 to theright and provide positive braking action by means of the brakingportion of the mechanism 28. Should the operator for any reason desireto reverse the direction of feed during the formation of the seam, suchas to produce a back tack at the leading edge of the material, forexample, the reversing lever 92 is actuated to change the direction ofmovement of the feed dog 72 along its elliptical path in the mannerdescribed heretofore.

As the operator of the machine inserts the leading edge of the materialinto the stitching mechanism 20, the beam of light from the light source100 to the photoelectric cell 98 is interrupted to produce an outputsignal in the winding of the relay 125 (FIGURE 8). The relay 125 is thusenergized to close its contacts 126, thereby conditioning themulticontact relay 128 for energization to control the sewing operationautomatically. The relay 128 remains deenergized at this point, however,because of the open circuit at the contacts 103.

In a similar manner, the leading edge of the material moving beneath thelight source 1151 (FIGURE 9) interrupts the light beam therefrom toproduce an output si nal in the winding of the relay 156, therebyenergizing the relay and closing its contacts 157. As these contactsclose, one terminal of the relay winding 160a is connected to the supplyline 126, but the relay 160 remains deenergized because of the opencontacts 104 between the opposite terminal of the winding 166a and thesupply line 121. The machine is thus conditioned for automaticoperation.

The formation of the seam continues under the manual control of the foottreadle 51 until such time as the operator actuates the automaticcontrol lever 97. The lever 97 may be operated at substantially anyconvenient point during the formation of the seam. Upon actuation of thelever, the contacts 103 and 194 close momentarily to initiate automaticoperation of the machine under the control of the take-over solenoid 44,the braking solenoid 46, the treadle release solenoid 66 and thereversing solenoid 94.

Referring to FIGURE 8, the closure of the contacts 163 completes acircuit for the winding 128a of the multicontact re-lay 128. Thiscircuit follows a path from the supply line 121), the two-positionswitch 111 and the relay contacts 126 to one terminal of the winding128a and from the opposite terminal of the winding through the conductor129, the contacts 103 and the conductors 130 and 131 to the supply line121. The relay 128 is thus energized to close the contacts 132 and 133and to transfer the contact 138 from the contact 139 to the contact 140.The closure of the contacts 132 completes a holding circuit for therelay winding, While the closure of the contacts 133 is effective toenergize the take-over solenoid 44 and the treadle release solenoid 66.The energizing circuit for the solenoids 44 and 66 may be traced fromthe line 126, the conductor 135 and the contacts 133 to one commonterminal of the solenoids and then back from the other common terminalthrough the twoposition switch 112 and the conductor 136 to the supplyline 121. As the contact 138 transfers from the contact 139 to thecontact 140, a circuit is completed from the supply line 120, theconductor and the contacts 138 and 140 to the negative terminal of thecondenser 142 and from the positive terminal of this condenser throughthe rectifier 148 and the resistor 149 to the supply line 121, therebycharging the condenser to a DC. potential.

The energization of the take-over solenoid 44 moves its plunger 43(FIGURE 1) in a downward direction to similarly move the offset lever 42and the plate 41. The L-shaped lever 39 thereupon pivots about the pin40 to urge the actuating pin 34 of the clutch-brake mechanism 28 in adirection to continuously engage the clutch portion of the mechanism.Simultaneously, the ener-gization of the treadle release solenoid 66pivots the lever 60 in a counterclockwise direction, as viewed in FIGURE6, to withdraw the lever from the locking portion 62 of the elongatedrod 53. As the lever 61) moves away from the portion 62, the rod 53 isfree to slide in an axial direction relative to the rod 52. Theconnection between the foot treadle 51 and the clutch-brake mechanism 28is thus interrupted as long as the solenoid 66 remains energized.

As the contacts 104 (FIGURE 9) close in response to the operation of thelever 97, an energizing circuit is completed for the winding a of themu-lticontact relay 160. This circuit may be traced from the supply line120, the conductor 158, the relay contacts 157, the winding 160a, therelay contacts 162 and 163, the contacts 164 and the conductors 165 and166 to the supply line 120. Upon the energization of the relay 160, thecontact 162 transfers from the contact 163 to the contact 164, therebycompleting a holding circuit for the winding 1612a, and the contact 167transfers from the contact 168 to the contact 169. The engagement of thecontacts 167 and 169 serves to connect the negative side of thecondenser 17!) to the supply line 120, thus placing a charge across thecondenser. The relay 172 remains in its deenergized condition at thispoint, however, because of the break in the circuit between the contacts167 and 168.

As the trailing edge of the material being sewn reaches the stitchingmechanism 20, the interruption of the light beam from the source 191 isdiscontinued. The light from the source 101 again strikes the photocell99 to deenergizc the relay 156, thereby opening the contacts 157 anddeenergizing the relay 161 The transfer contact 167 thereupon moves fromthe stationary contact 169 to the stationary contact 168, and adischarge path is completed for the condenser 170 through the winding ofthe relay 172. The relay 172 is thus energized for a period of timewhich is dependent upon the time constant of the con denser 170 and theresistance of the variable resistor 118 and the resistor 175.Energization of the relay 172 closes its contacts 182 to energize thereversing solenoid 94, thereby moving the lever 92 to the right, asviewed in FIGURE 1, to reverse the direction of feed of the material inthe manner described heretofore.

As indicated heretofore, the light source 101 is supported adjacent thestitching mechanism 20. The position of the source 101 is such that theenergization of the reversing solenoid 94 takes place at the same timethat the trailing edge of the material passes beneath the stitchingmechanism and the last stitch is completed. The operation of the feedingmechanism continues in the reversed directon until the condenser 170discharges sufficiently to permit deenergization of the relay 172.During the discharge of the condenser, the stitching mechanismillustratively produces from six to twelve back tacking stitches whichare superimposed over the forward line of stitching adjacent thetrailing edge of the material. Upon the deenergization of the relay 172,the contacts 182 open to deenergize the reversing solenoid 94. Theoperation of the feeding mechanism in the forward direction is thereuponautomatically resumed to produce an additional line of forward stitchingat the trailing edge.

As the trailing edge of the material passes beneath the light source 100(FIGURE 8), its light beam again reaches the photocell 98, therebydeenergizing the relay 125. Upon the deenergization of this relay, thecontacts 126 open to deenergize the multicontact relay 128 and open thecontacts 132 and 133. The opening of the contacts 132 breaks the holdingcircuit for the relay winding 128a, while the opening of the contacts133 is effective to deenergize the take-over solenoid 44 and the treadlerelease solenoid 66. The solenoid 44 is thus no longer effective to holdthe actuating pin 34 (FIGURE 1) for the clutch-brake mechanism 28 in itsclutch-engaged position. Deenergization of the solenoid 66 releases thespring biased lever 60 (FIGURES 6 and 7), and the lever 60 rides againstthe cylindrical surface of the rod 53 until such time as the lockingportion 62 of this rod is moved to a position adjacent the lever. Thespring 64 thereupon draws the lever into contact with the lockingportion to reestablish the connection between the foot treadle 51 andthe clutch-brake mechanism 28.

The deenergization of the multicontact relay 128 also is effective totransfer the movable contact 138 from the stationary contact 140 to thestationary contact 139. A discharge path is thus completed for thecondenser 142 through the winding of the relay 145. This relay isthereupon energized for a period of time which is dependent upon thetime constant of the condenser 142 and the resistance of the variableresistor 117 and the resistor 147. Upon energization of the relay 145,its contacts 152 close to energize the braking solenoid 46, therebyactuating the levers 42 and 39 (FIGURE 1) in a direction to operate thebraking portion of the clutch-brake mechanism 28 in the manner describedabove. The stitching and feeding mechanisms of the machine are thusrapidly and automatically brought to a stop.

The variable resistor 117 is adjusted by the operator of the machine toinsure that the condenser 142 discharges through the winding of therelay 145 for a period of time sufficient to maintain the brakingsolenoid 46 energized until the machine has come to a complete stop. Ina similar manner, the variable resistor 118 is adjusted to predeterminethe time during which the reversing solenoid 94 remains energized tooperate the feeding mechanism in the reverse direction. The resistor 118thus provides a precise control over the length of the back tack.

Referring to FIGURES 10 and 11, there is shown a portion of a sewingmachinewhich is representative of another illustrative embodiment of theinvention. The machine 185 includes a light source 186 and a cooperatingphotocell 187 which are mounted on a plate 188 by means of a bracket189. A light source 190 and a photocell 191 similarly are secured by abracket 192 to a plate 193. The plates 188 and 193 are fixedly butadjustably fastened by screws 195 to a support plate 196 which iscarried adjacent the upper portion of the needle head 197 of themachine. The positions of the plates 188 and 193 may be readily variedby loosening the screws 195, to similarly vary the locations of thephotocells and light sources carried thereby.

Extending downwardly from the light sources 186 and 190 and thephotocells 187 and 191 are four elongated rods 200, 201, 202 and 203,respectively. These rods are fabricated of Lucite or other transparentmaterial. The upper ends of the rods 200 and 202 are attached to theplate 188 by a bracket 205, While the upper ends of the rods 201 and 203are secured to the plate 193 by a bracket 206. The lower ends of therespective pairs of rods are suitably held apart, as by brackets 207 and208, and are oriented in spaced juxtaposition with the reflective throatplate 210 of the machine.

In operation, the light beam from the source 186 passes along the rod2-00, is reflected by the throat plate 210 and is directed through therod 202 to the photocell 187. Similarly, the light beam from the source190 moves along the rod 201, is reflected by the plate 210 and thenpasses through the rod 203 to the photocell 191. These light beams aresuccessively interrupted as the leading edge of the material to be sewnpasses through the stitching mechanism of the machine. The sources 186and 190 and the photocells 187 and 191 are electrically connected in amanner similar to the sources 101 and 100 and the photocells 99 and 98,in that order, described heretofore. By employing the transparent rods200-203, the sources 186 and 190 and the photocells 187 and 191 may bemounted adjacent the upper portion of the machine in spaced relationshipwith the stitching mechanism to provide the operator with extremely goodvisibility of the line of stitching being sewn.

In the illustrated embodiments of the invention, the various photocells,light sources and cooperating circuitry are effective to perform certainof their automatic control functions in response to the appearance ofthe trailing edge of the material at the stitching mechanism of themachine. In other good arrangements, these components are responsive toother preselected portions of the material. As an illustration, thephotocell 99 (FIG- URE 9), the light source 101 and the associatedcircuitry may be employed to automatically reverse the direction of feedintermediate the edges of the material in response to a suitable changein color, pattern, etc., or upon the appearance of an appropriate markat a preselected point along the seam.

The terms and expressions which have been employed are used as terms ofdescription and not of limitation, and there is no intention in the useof such terms and expressions of excluding any equivalents of thefeatures shown or described or portions thereof, but it is recognizedthat various modifications are possible within the scope of theinvention claimed.

What is claimed is:

1. In a sewing machine having a power source and a stitching mechanismoperated by said power source, the combination comprising a feedingmechanism driven by said power source for advancing material throughsaid stitching mechanism, reversing means cooperating with said feedingmechanism for changing the direction of feed of said material, sensingmeans supported adjacent said stitching mechanism for producing anoutput signal upon the appearance of a preselected portion of saidmaterial thereat, and circuit means interconnecting said sensing meansand said reversing means for operating the same in response to saidoutput signal, to automatically change the direction of feed of thematerial for a predetermined period of time, said circuit meansincluding electrical discharge means cooperating with said reversingmeans for controlling the period of operation thereof.

2. In a sewing machine having a power source and a stitching mechanismoperated by said power source, the combination comprising a feedingmechanism driven by said power source for advancing material throughsaid stitching mechanism in a given direction, reversing meanscooperating with said feeding mechanism for changing the direction offeed of said material, first sensing means supported by said machine,means connected to said first sensing means and cooperating with saidfeeding mechanism for automatically feeding said material through saidstitching mechanism in said given direction, second sensing meanssupported by said machine for producing an output signal upon theappearance of a preselected portion of said material at said stitchingmechanism, and means interconnecting said second sensing means and saidreversing means for o erating the same in response to said outputsignal, to automatically change the direction of feed of the materialfor a predetermined period of time, said feeding mechanism thereaftercontinuing to advance said material through said stitching mechanism insaid given direction.

3. In a sewing machine having a power source and a stitching mechanismoperated by said power source, the combination comprising a feedingmechanism driven by said power source for advancing material throughsaid stitching mechanism, manually operable reversing means cooperatingwith said feeding mechanism for changing the direction of feed of saidmaterial, first sensing means supported by said machine, means connectedto said first sensing means and cooperating with said feeding mechanismfor automatically feeding said material through said stitching mechanismin a forward direction, second sensing means supported adjacent saidstitching mechanism for producing an output signal upon the appearanceof a preselected portion of asid material thereat, and meansinterconnecting said second sensing means and said reversing means foroperating the same automatically in response to said output signal, tochange the direction of feed of the material.

4. In a sewing machine having a power source and a stitching mechanismoperated by said power source, the combination comprising a feedingmechanism driven by said power source for advancing material throughsaid stitching mechanism in a given direction, reversing meanscooperating with said feeding mechanism for changing the direction offeed of said material, manually operable means, connections between saidmanually operable means and said feeding mechanism for operating thesame under manual control, circuit means for automatically operatingsaid feeding mechanism to advance said material through said stitchingmechanism in said given direction independently of said manuallyoperable means, photoelectric means supported adjacent said stitchingmechanism for producing an output signal upon the appearance of apreselected portion of said material thereat, and means interconnectingsaid photoelectric means and said reversing means for operating the samein response to said output signal during the automatic operation of saidfeeding mechanism to change the direction of feed of the material for apredetermined period of time, said feeding mechanism thereaftercontinuing the automatic advance of said material through said stitchingmechanism in said given direction under the control of said circuitmeans.

5. In a sewing machine having a power source and a stitching mechanismoperated by said power source, the combination comprising a feedingmechanism driven by said power source for advancing material throughsaid stitching mechanism in a given direction, reversing meanscooperating with siad feeding mechanism for changing the direction offeed of said material, circuit means cooperating with said feedingmechanism for matically controlling the same, said circuit meansincluding a manually operable switch for initiating the automaticoperation of said feeding mechanism at substantially any point duringthe advance of said material through said stitching mechanism,photoelectric means supported adjacent said stitching mechanism forproducing an output signal upon the appearance of a preselected portionof said material thereat, and means interconnecting said photoelectricmeans and said reversing means for operating said reversing means inresponse to said output signal during the automatic operation of saidfeeding mechanism, to change the direction of feed of the material for apredetermined period of time, said feeding mechanism thereaftercontinuing the automatic advance of said material through said stitchingmechanism in said given direction under the control of said circuitmeans.

6. In a sewing machine having a power source and a stitching mechanismoperated by said power source, the combination comprising a feedingmechanism driven by said power source for advancing material throughsaid stitching mechanism in a given direction, reversing meanscooperating with said feeding mechanism for changing the direction offeed of said material, manually operable means, connections between saidmanually operable means and said feeding mechanism for operating thesame under manual control, circuit means for automatically operatingsaid feeding mechanism to advance said material through said stitchingmechanism in said given direction independently of said manuallyoperable means, said circuit means including a switch controlled by theoperator of the machine for initiating the automatic operation of saidfeeding mechanism at substantially any point during the advance of saidmaterial through said stitching mechanism, photoelectric means supportedby said machine for producing an output signal upon the appearance of apreselected portion of said material at said stitching mechanism, andmeans interconnecting said photoelectric means and said reversing meansfor operating the same in response to said output signal during theautomatic operation of said feeding mechanism, to change the directionof feed of the material for a predetermined period of time, said feedingmechanism thereafter continuing the automatic advance of said materialthrough said stitching mechanism in said given direction under thecontrol of said circuit means.

7. In a sewing machine of the character set forth in claim 6, saidphotoelectric means including a photoelectric cell and a light sourcefor directing a beam of light toward said cell, said beam of light beinginterrupted by the material being advanced through said stitchingmechanism.

8. In a sewing machine having a power source and a stitching mechanismoperated by said power source, the combination comprising a feedingmechanism connected to said power source for advancing material throughsaid stitching mechanism in a given direction, reversing meanscooperating with said feeding mechanism for changing the direction offeed of said material, circuit means connected to said feeding mechanismfor automatically controlling the same, said circuit means including amanually operable switch for initiating the automatic operation of saidfeeding mechanism at substantially any point during the advance of saidmaterial through said stitching mechanism, photoelectric means supportedadjacent said stitching mechanism for producing an output signal uponthe appearance of a preselected portion of said material thcreat, meansinterconnecting said photoelectric means and said reversing means foroperating said reversing means in response to said output signal duringthe automatic operation of said feeding mechanism, to change thedirection of feed of the material for a predetermined period of time,said feeding mechanism thereafter continuing the automatic advance ofsaid material through said stitching mechanism in said given directionunder the control of said circuit means, and means controlled by saidcircuit means for disconnecting said feeding mechanism from said powersource as the trailing edge of said material leaves said stitchingmechanism.

9. In a sewing machine having a power source and a stitching mechanismoperated by said power source, the combination comprising a reversiblefeeding mechanism driven by said power source for advancing materialthrough said stitching mechanism, first manually operable means,connections between said first manually operable means and said feedingmechanism for operating the same under manual control, second manuallyoperable means for controlling said feeding mechanism to reverse thedirection of feed of the material, circuit means for automaticallyoperating said feeding mechanism to advance said material through saidstitching mechanism in a given direction independently of said firstmanually operable means, photoelectric means supported adjacent saidstitching mechanism for producing an output signal upon the appearanceof a preselected portion of said material thereat, and meansinterconnecting said photoelectric means and said second manuallyoperable means for operating the same automatically in response to saidoutput signal during the automatic operation of said feeding mechanism,to change the direction of feed of the material for a predeterminedperiod of time, said feeding mechanism thereafter continuing theautomatic advance of said material through said stitching mechanism insaid given direction under the control of said circuit means.

10. In a sewing machine having a power source and a stitching mechanismoperated by said power source, the combination comprising a reversiblefeeding mechanism driven by said power source for advancing materialthrough said stitching mechanism, means interconnecting said powersource and said feeding mechanism, reversing means for controlling saidfeeding mechanism to reverse the direction of feed of the material,first photoelectirc means supported by said machine, circuit meansconnected to said first photoelectric means and cooperating with saidfeeding mechanism for automatically feeding said material through saidstitching mechanism in a forward direction, second photoelectric meanssupported by said machine for producing an output signal upon theappearance of a preselected portion of said material at said stitchingmechanism, and means interconnecting said second photoelectric means andsaid reversing means for automatically actuating said reversing means inresponse to said output signal, to change the direction of feed of thematerial for a predetermined period of time, said circuit meansthereafter continuing the automatic feeding of said material throughsaid stitching mechanism in said forward direction.

11. In a sewing machine having a power source and a stitching mechanismoperated by said power source, the combination comprising a reversiblefeeding mechanism driven by said power source for advancing materialthrough said stitching mechanism, means interconnecting said powersource and said feeding mechanism, reversing means for controlling saidfeeding mechanism to reverse the direction of feed of the material,first sensing means supported adjacent said stitching mechanism, circuitmeans interconecting said first sensing means and said feeding mechanismfor automatically feeding said material through said stitching mechanismin a forward direction, second sensing means supported on the infeedside of said stitching mechanism, for producing an output signal uponthe appearance of the trailing edge of said material thereat, and meansconnected to said second sensing means and responsive to said outputsignal for automatically actuating said reversing means, to reverse thedirection of feed of the material for a predetermined period of time,said circuit means thereafter continuing the automatic feeding of saidmaterial through said stitching mechanism in said forward direction.

12. In a sewing machine having a power source and a stitching mechanismoperated by said power source, the combination comprising a reversiblefeeding mechanism driven by said power source for advancing materialthrough said stitching mechanism, means interconnecting said powersource and said feeding mechanism, reversing means for controlling saidfeeding mechanism to reverse the direction of feed of the material,first photoelectric means supported adjacent said stitching mechanism,circuit means connected to said first photoelectric means andcooperating with said feeding mechanism for automatically feeding saidmaterial through said stitching mechanism in a forward direction, secondphoto electric means supported on the infeed side of said stitchingmechanism for producing an output signal upon the appearance of thetrailing edge of said material thereat, and means connected to saidsecond photoelectric means and responsive to said output signal forautomatically actuating said reversing means, to reverse the directionof feed of the material for a predetermined period of time, said circuitmeans thereafter continuing the automatic feeding of said materialthrough said stitching mechanism in said forward direction and includingmeans for automatically arresting said feeding mechanism as the trailingedge of said material leaves said stitching mechanism.

13. In a sewing machine having a power source and a stitching mechanismoperated by said power source, the combination comprising a reversiblefeeding mechanism driven by said power source for advancing materialthrough said stitching mechanism, means interconnecting said powersource and said feeding mechanism, reversing means for controlling saidfeed-ing mechanism to reverse the direction of feed of the material,first photoelectric means supported by said machine and having a firstlight path which is interrupted as said material enters said stitchingmechanism, the interruption of said first light path conditioning saidmachine for automatic operation, circuit means connected to said firstphotoelectric means and cooperating with said feeding mechanism forautomatically feeding said material through said stitching mechanism ina forward direction, said circuit means including a switch controlled bythe operator of the machine for initiating the automatic operation ofsaid feeding mechanism at substantially any point during the advance ofsaid material through said stitching mechanism, second photoelectricmeans supported by said machine and having a second light path which iscompleted as the trailing edge of said material reaches said stitchingmechanism, and means connected to said second photoelectric means andresponsive to the completion of said second light path for automaticallyactuating said reversing means, to reverse the direction of feed of thematerial for a predetermined period of time, said circuit meansthereafter continuing the automatic feeding of said material throughsaid stitching mechanism in said forward direction.

14. In a sewing machine of the character set forth in claim 13, saidfirst and second photoelectric means being supported on said machine inspaced relationship With said stitching mechanism, and means including aplurality of light conducting members for transmitting light from saidphotoelectric means along portions of said light paths to said stitchingmechanism.

15. In a sewing machine having a power source and a stitching mechanismoperated by said power source, the combination comprising a reversiblefeeding mechanism driven by said power source for advancing materialthrough said stitching mechanism, clutch means interconnecting saidpower source and said feeding mechanism, manually operable means,connections between said manually operable means and said clutch meansfor engaging and disengaging the same, reversing means for controllingsaid feeding mechanism to reverse the direction of feed of the material,first photoelectric means supported adjacent said stitching mechanismand having a first light path which is interrupted as said materialenters said stitching mechanism, the interruption of said first lightpath conditioning said machine for automatic operation, circuit meansconnected to said first photoelectric means for maintaining said clutchmeans in a continuously engaged condition and for interrupting theconnections between said clutch means and said manually operable means,to automatically feed said material in a forward direction independentlyof said manually operable means, second photoelectric means supportedadjacent said stitching mechanism and having a second light path whichis completed as the trailing edge of said material reaches saidstitching mechanism, and means connected to said second photoelectricmeans and responsive to the completion of said second light path forautomatically actuating said reversing means, to reverse the directionof feed of the material for a predetermined period of time, said circuitmeans thereafter continuing the automatic feeding of said materialthrough said stitching mechanism in said forward direction.

16. In a sewing machine having a power source and a stitching mechanismoperated by said power source, the combination comprising a reversiblefeeding mechanism driven by said power source for advancing materialthrough said stitching mechanism, clutch means interconnecting saidpower source and said feeding mechanism, first manually operable means,connections between said first manually operable means and said clutchmeans for engaging and disengaging the same second manually operablemeans for controlling said feeding mechanism to reverse the direction offeed of the material, first photoelectric means supported by saidmachine and having a first light path which is interrupted as saidmaterial enters said stitching mechanism, the interruption of said firstlight path conditioning said machine for automatic operation, circuitmeans connected to said first photoelectric means for maintaining saidclutch means in a continuously engaged condition and for interruptingthe conneclions between said clutch means and said first manuallyoperable means, to automatically feed said material in a forwarddirection independently of said first manually operable means, secondphotoelectric means supported by said machine and having a second lightpath which is completed as the trailing edge of said material reachessaid stitching mechanism, and means connected to said secondphotoelectric means and responsive to the completion of said secondlight path for automatically actuating said second manually operablemeans, to reverse the direction of feed of the material for apredetermined period of time, said circuit means thereafter continuingthe automatic feeding of said material through said stitching mechanismin said forward direction.

17. In a sewing machine having a power source and a stitching mechanismoperated by said power source, the combination comprising a reversiblefeeding mechanism driven by said power source for advancing materialthrough said stitching mechanism, clutch means interconnecting saidpower source and said feeding mechanism, first manually operable means,connections between said first manually operable means and said clutchmeans for engaging and disengaging the same, second manually operablemeans for controlling said feeding mechanism to reverse the direction offeed of the material, first photoelectric means supported adjacent saidstitching mechanism and having a first light path which is interruptedas the leading edge of said material is inserted into said stitchingmechanism, the interruption of said first light path conditioning saidmachine for automatic operation, circuit means connected to said firstphotoelectric means for maintaining said clutch means in a continuouslyengaged condition and for interrupting the connections between saidclutch means and said first manually operable means, to automaticallyfeed said material in a forward direction independently of said firstmanually operable means, said circuit means including a switchcontrolled by the operator of the machine for initiating the automaticoperation of said feeding mechanism at substantially any point duringthe advance of said material through said stitching mechanism, secondphotoelectric means supported on the infeed side of said stitchingmechanism and having a second light path which is completed as thetrailing edge of said material reaches said stitching mechanism, andmeans connected to said second photo electric means and responsive tothe completion of said second light path for automatically actuatingsaid second manually operable means, to reverse the direction of feed ofthe material for a predetermined period of time, said circuit meansthereafter continuing the automatic feeding of said material throughsaid stitching mechanism in said forward direction.

18. In a sewing machine having a power source and a stitching mechanismoperated by said power source, the combination comprising a reversiblefeeding mechanism driven by said power source for advancing materialthrough said stitching mechanism, clutch means interconnecting saidpower source and said feeding mechanism, first manually operable means,connections between said first manually operable means and said clutchmeans for engaging and disengaging the same, second manually operablemeans for controlling said feeding mechanism to reverse the direction offeed of the material, first photoelectric means supported adjacent theoutfeed side of said stitching mechanism and having a first light pathwhich is interrupted as the leading edge of said material is insertedinto said stitching mechanism, the interruption of said first light pathconditioning said machine for automatic operation, circuit meansconnected to said first photoelectric means for maintaining said clutchmeans in a continuously engaged condition and for simultaneouslyinterrupting the connections between said clutch means and said firstmanually operable means, to automatically feed said material in aforward direction independently of said first manually operable means,said circuit means including a switch controlled by the operator of themachine for initiating the automatic operation of said feeding mechanismat substantially any point during the advance of said material throughsaid stitching mechanism, second photoelectric means supported adjacentsaid stitching mechanism and having a second light path which iscompleted as the trailing edge of said material reaches said stitchingmechanism, means connected to said second photoelectric means andresponsive to the completion of said second light path for automaticallyactuating said second manually operable means, to reverse the directionof feed of the material for a predetermined period of time, said circuitmeans thereafter continuing the automatic feeding of said materialthrough said stitching mechanism in said forward direction, and meanscontrolled by said circuit means for disengaging said clutch means asthe trailing edge of said material leaves said stitching mechanism andfor simultaneously braking said feeding mechanism.

References Cited UNlTED STATES PATENTS 3,024,750 3/1962 Winz 112-2033,080,836 3/1963 Clemens et al 112-2 X 2,052,896 9/1936 Roseman 1l2203 XRICHARD J. SCANLAN, In, Primary Examiner.

